A Pedestrian Traffic Signal Control Method by Use of Image Processing and Entropy

在十字路口旁的建筑上安装了摄像头，在人行横道上连续拍摄行人交通图像。利用图像处理从拍摄的图像中获得行人的空间分布。提出了一种利用信息熵来量化行人空间分布格局、宏观估计行人交通需求的方法，提出了一种利用图像处理和信息熵调整行人绿灯持续时间的行人交通信号控制方法。这是一种根据熵值估计行人交通需求，并根据该熵值优化每个信号周期的行人绿灯时长的方法。通过将该方法应用于交叉口，可以排除行人绿灯的多余时间。因此，我们可以期待特别是缓解从拥挤的十字路口延伸出来的交通拥堵。基于图像处理结果和仿真实验，研究了行人交通需求减少时绿灯切换为绿灯的熵阈值。由于交通信号控制的最小周期为1秒，因此提出了一种简单的图像处理和信息熵测量方法，可以在1秒内完成处理；对于老年人和残疾人等慢行行人，提出了一种具有安全功能的行人交通信号控制方法)将行人绿灯变为绿灯后，通过图像处理检测到这样的行人，绿灯闪烁的持续时间延长，直到行人在人行横道上通过。

A video camera is installed on a building beside an intersection, and pedestrian traffic images are taken continuously on a crosswalk. A spatial distribution of pedestrians is obtained from a taken image by use of image processing. We have developed a method to quantify the spatial distribution pattern of pedestrians using entropy, and to estimate macroscopically pedestrian traffic demand.In this study, we propose a pedestrian traffic signal control method to adjust the duration of pedestrian green lights by use of image processing and entropy. This is a method to estimate the pedestrian traffic demand from an entropy value, and to optimize the pedestrian green signal duration every signal cycle according to the entropy value. By applying this method to an intersection, a redundant time of pedestrian green lights can be excluded. Therefore, we can expect especially to relieve the traffic jams extended from a scramble intersection. Entropy threshold values to switch from the green lights to the green winking when pedestrian traffic demand decreases was examined based on the image processing results and the simulation experiments. As a result, we obtained optimal threshold values, 2.5 bits at a usual crosswalk and 3.0 bits at a scramble intersection.Since the minimum cycle of traffic signal control is one second, a simple image processing and entropy measurement method is developed to complete the processing within one second.We also propose a pedestrian traffic signal control method with a safety function for the slow walking pedestrian such as elderly person and physically handicapped person) if such a pedestrian is detected by the image processing after changing pedestrian green lights to green winking, the green winking duration is extended until the pedestrian finishes crossing at the crosswalk.